Melphalan is a phenylalanine derivative comprising L-phenylalanine having [bis(2-chloroethyl)amino group at the 4-position on the phenyl ring. It has a role as an antineoplastic agent, a carcinogenic agent, an alkylating agent, an immunosuppressive agent and a drug allergen. It is an organochlorine compound, a nitrogen mustard, a L-phenylalanine derivative and a non-proteinogenic L-alpha-amino acid.